Question

15 the biological half - life of fructose, the time required for the body to eliminate one - half of the total amount of fructose, for an individual is 20 minutes. which statement about the amount of fructose in the individuals body is correct? a. of a 192 mg dose of fructose, less than 1 mg of fructose will still be in the individuals system 80 minutes after the dose is taken. b. of a 192 mg dose of fructose, about 12 mg of fructose will still be in the individuals system 80 minutes after the dose is taken. c. of a 192 mg dose of fructose, 0 mg of fructose will still be in the individuals system 80 minutes after the dose is taken. d. of a 192 mg dose of fructose, about 24 mg of fructose will still be in the individuals system 80 minutes after the dose is taken.

Explanation:

Step1: Calculate number of half - lives

The half - life of fructose is 20 minutes and the time elapsed is 80 minutes. The number of half - lives $n=\frac{80}{20}=4$.

Step2: Use half - life formula

The amount of a substance remaining after $n$ half - lives, given an initial amount $A_0$, is $A = A_0\times(\frac{1}{2})^n$. Here, $A_0 = 192$ mg and $n = 4$. So $A=192\times(\frac{1}{2})^4$.

Step3: Calculate remaining amount

$A = 192\times\frac{1}{16}=12$ mg.

Answer:

B. Of a 192 mg dose of fructose, about 12 mg of fructose will still be in the individual's system 80 minutes after the dose is taken.